Cutter for trimming rinds from molded articles



E. N. BRODEN Jan. 29, 1957 CUTTER FOR TRIMMING RINDS FROM MOLDEDARTICLES Original Filed Sept. 15 1951 3 She ets-Sheet 1 IN V EN TOR.

y tam/v N. 00005 ATTORNEYS E- N. BRODEN Jan. 29, 1957 CUTTER FORTRIMMING RINDS FROM MOLDED ARTICLES 3 Sheets-Sheet 2 Original FiledSept. 15, 1951 INVENTOR. ZZZ/W7 5'519171757 BY United States PatentCUTTER FOR TRHWMIN G RINDS FROM MOLDED ARTICLES Edwin N. Braden,Assonet, Mass, assignor to The Firestone Tire & Rubber Company, Akron,Ohio, a corporation of Ohio Original application September 15, 1351,Serial No. 246,747. Divided and this application December 12, 1952,Serial No. 334,033

10 Claims. (Cl. 164-63) This invention relates to a cutter for trimmingrinds from molded, vulcanized articles and, in particular, has to dowith the trimming of articles of circular outline, such as casterwheels. In the molding of such articles, outflow between the moldsections results in a circumferential flash or rind and, depending uponthe particular mold employed, this may occur in a single line centrallyof the rolling face of the wheel being molded, or it may occur at thecorners between the rolling face and the respective side faces. Theembodiment of the machine which is shown herein is designed to trimwheels having two rinds, but the principles of the invention may beadapted to the trimming of wheels with only one rind. This patentapplication is a division of my copending United States patentapplication Serial No. 246,747 filed September 15, 1951 and nowabandoned.

Heretofore rinds on caster wheels or similar articles have been removedby hand methods, wherein the excess rubber is sheared oil or abraded.Obviously, such methods are prohibitively time consuming. According tothe present invention, the articles are neatly trimmed, automaticallyand rapidly, by mounting them on a turntable and indexing them to aposition adjacent a pair of driven, overlapping circular knives, whichare thereupon moved into cutting engagement with'the rind, and theknives, in severing the rind, also rotate the article.

It is therefore an object to provide a rind-severing device which iscertain in its action. More particularly, it is an object to provide arind-severing machine in which a rotary cutting device is moved intoengagement with the work to be cut, after the work has been indexed to astop.

While the invention is shown as it is applied to the trimming of casterwheels, with appropriate changes the principles of the invention may beused in machines or apparatus for trimming other round or disk-likearticles. It will also be appreciated that while the details of the bestknown and preferred forms of the cutterare illustrated and described,the invention is subject to modifications and improvements within thescope of the invention as set forth in the appended claims.

' The objects of the invention are attained by the present invention, apreferred embodiment of which is described in the accompanyingspecification and illustrated in the drawings, in which:

Figure 1 is a top plan view of the cutting machine with parts brokenaway.

Figure 2 is an elevation view of the cutting machine of Figure 1.

Figure 3 is a view taken along the line 3-3 of Figure 1.

Figure 4 is a view taken along the line 4-4 of Figure 1.

Figure 5 is an enlarged view in side elevation ofone of the cuttingunits shown in Figures land 2.

Figure 6 is a top plan view of Figure 5.

Figure 7 is an elevation view of the cutting unit of Figure 5 as seenfrom the left of that figure.

Referring to the drawings by characters of reference, there is shown abed plate 1, having a central, upright,

cylindrical pedestal 2 with a reduced upper end 3, on which is rotatablymounted a turntable 4 and a ratchet wheel 6 which is attached to theturntable. Also rotatably mounted on reduced end 3 of the shaft is thehub 7 of a radius arm 8, carrying a pin 9 near its outer end,

, on which is pivoted a pawl 11 adapted to engage in notches 12 in theratchet wheel, to rotate the turntable. This rotation is clockwise; Aspring 13 urgesthe pawl constantly toward the ratchet wheel. Backrotation of the turntable is prevented by a second pawl'S, pivoted at 10to the bed plate, and having a spring 15 biasing a tooth 5' on the pawlinto engagement in notches 12.

The radius arm 8 is reciprocated by a link 14 having one end pivotedthereto, as at 16, and its other end pivoted cccentrically, as at 17, ona disk 18 connected to the output shaft 18' of a reduction gearing unit19. The latter is driven by a motor 21 through a belt 22. Thus, theindexing of the turntable by the pawl occurs in timed relation to theoutput of the motor. The motor also drives the trimming knives, later tobe described and, therefore, the indexing occurs in timed relation tothe rotation of the trimming knives also.

At its outer periphery, the turntable has circumferentially spacedradially extending fingers 23, rotatably mounting upstanding pegs 24with base flanges 26, the pegs being adapted to receive the centralopening of a caster wheel 27, which is to be trimmed.

The particular caster wheels shown are of the type cured in three-piecemolds, and hence have two rinds 28, 29 at the edges of the tread. Theserinds are trimmed in successive stages by a pair of units indicatedgenerally by the respective numerals 31 and 32. Since these units arestructurally identical, except for the arrangement of the circularknives, only one unit need be described in detail.

Mounted on an outwardly extending bracket 33, secured to bed plate 1, isan upright shaft 34 threaded into a bore in a boss 33' on the saidbracket and secured by a lock nut 36. A block 37 has a bore 38 receivedon shaft 34 whereby the said block is slidable vertically. Adjustment ofthe vertical position of block 37 is effected by a screw 39 threadedinto the top of shaft 34. A bracket 41, bolted to the block 37, has ahorizontal shelf,

head 45 on the screw. Collar 43 may be an integral part of the screw.The block 37 is locked in adjusted position on shaft 34 by means of apair of wedge pins 46, 47 (Fig. 6) slidable in a bore 48 in the block37, intersecting the bore 38 which receives shaft 34 and transversethereto. lhe inner end of each pin has a tapered portion 49 adapted tocontact shaft 34, and the pins are drawn together by a bolt 51 slidablein an axial bore. in pin 46 and in axially threaded engagement with pin47.

Mounted in block 37 for sliding motion are a pair of rods 52, 53,arranged generally horizontal and perpendicular to shaft 34. Slidingadjustment of these rods is effected by a screw 54 threaded in block 37and secured by a lock out 50. Screw 54 is anchored in a cross-piece S6of generally triangular form, which is secured by screws 57 in the endsof rods 52, 53, the screw being restrained against axial motion relativeto the cross-piece by a hub 58 of a hand screw 55, and a collar 59.

A vertical sleeve 61 is supported on the other ends of rods 52, 53, thelatter being secured], respectively, in tubular bosses 62, 63 extendingfrom the sleeve. A pin 64, mounted for rotation in sleeve 61, has a head66 to which is secured an angle bracket 67 by means of a bolt 68. Theupright leg of bracket 67 is secured by a bolt 69 to a boss 70 on ahousing 71 carrying the trimmers and their gearing.

Rotation of pin 64 in the sleeve i 3 61 causes swing of the trimmers toand from the turntable.

By tightening the bolt 69, the knife housing 71 may be held in anydesired angular position. In Fig. 5, the trimming unit is shown invertical position, such as it would occupy if the machine were beingused for trimming a rind from the center of the tread. In Fig. 3, theunit 31 is tilted forwardly to trim the rind along the top edge of thearticle.

The mechanism for rotating pin 64 to swing the trimmers is described asfollows: Sleeve 61 has an arcuately extending opening '72 (Fig. throughwhich extends a rod 73 threaded into or otherwise secured to pin 64. Rod73 has a headed portion '74 with a flattened end 76. pivoted by a pin 77to a clevis 78, into which is threaded the reduced outer end 79 of thepiston rod 81 of an air cylinder 31. Attachment of air cylinder 31 tocross-piece 56 is had by means of a rod 82 secured by a screw 83 to thecross-piece and having a fiat end 84 on which is pivoted, by a pin 86, afork 87, which is secured by screws 33 to the air cylinder 81.

The air cylinder is of conventional type, the details of which are shownin Fig. 6, wherein a piston is urged out wardly by air pressure and isreturned by spring pressure.

. The arrangement is such that the air pressure urges the knife housingaway fromthe work and the spring 3111 pressure moves the knife housingtoward the work. Air under pressure is supplied to the two units throughpiping 85' from a suitable source through a common control valve of anyconventional type located in housing 85 mounted on the bed plate 1 at apoint where one of the work supporting fingers 23 comes to rest. Asimilar line leads from the valve mechanism to the unit 332 so that thetwo trimming units will move toward and from the work simultaneously.The air pressure in cylinder 81 is rework by air pressure in cylinder81.

The knife housing 71 comprises a system of gearing which permitsconsiderable latitude in the distance between the centers of the pair ofcircular knives 91, 92. Thus the knives maybe sharpened repeatedly,without any malfunctioning resulting from the reduction of their radii,and their useful life is therefore increased manifold.

The knife-drive gearing (Fig. 7), journaled in housing 71, comprises adriving gear 93 and a set of serially meshed gears 94, 95, 96, 97. Gear94 is keyed to a shaft 98 journaled in housing '71, and lower knife 92is also keyed to this shaft. Gears 95 and 96 are idlcrsmounted onrespective shafts 99, 191, which are iournaled in housing 71.

Gear 97 is keyed to a shaft 102, to which the upper knife 91 is alsokeyed. Shaft 102 is journaled in a. housing 1% having a pair of arms MMjournaled on shaft 1M and spanning the housing 71, so that the upperknife is swingable about shaft 191 without disengagement of gear 97 fromgear 95. Gears 94, 95 and 97 are of equal pitch diameter so that knives91, 92 will rotate at the same speed. It will be seen that, with thisarrangement, knives 91 and92 rotate in opposite directions and thatshaft m2 of knife 91 may be moved toward shaft 98 of knife 92 withoutinterfering with the effective transmission of power through the geartrain. The upper knife is held in its adjusted position by bolts 1%,which pass through the curved slots ltltl in the arms 194 and arethreaded in the sides of the housing 71.

The drive to gear 93 is through a flexible shaft 1% leading from themotor 21. The power input to trimmer unit 32 is through a flexible shaft107 leading from the input of gear reduction unit 19, which input hasthe same angular speed as motor 21. Thus the two sets of trimmer diskshave equal angular speeds. Since the reduction gear unit 19 operates intimed relation to the motor, and hence to the circular knives, the pawl11 will advance the ratchet wheel 6 one step, at the end of apredetermined number of revolutions of the knives, which will be one ormore revolutions as required for effective trimming.

The knives of the unit 31 shown in Fig. 3 are constructed and arrangedto cut the rind 28 from the top edge of the rolling face of a wheel.

Upper knife 91 has a planar face 108 facing housing 71, a beveled face1tl9 meeting face 1% in a cutting edge, and an outer, planar face 111.This knife is secured on a threaded, reduced end of shaft 102 by a nut112. Lower knife 92, the overall thickness of which is somewhat greaterthan knife 91, has an annular planar face 113 surrounding a centralcavity 114 in the outer face of the knife and has a beveled face 116 onits inner side meeting face 113 in a cutting edge. This knife is securedto its shaft 98 by nut 117'. The faces 108 and 113 of the respectiveknives are in contact near their peripheries, the preferred amount ofradial overlap being about inch for knives having a diameter of about2%; inches.

The cavity 114 is provided to give clearance for the crown on therolling face of the wheel 27. With the axis of caster wheel 27 vertical,the housing 71 is inclined somewhat to the vertical so that the plane ofthe contacting, flat faces of the knives is transverse to the rind 28.This plane is substantially tangential to the peripheral surface ofwheel 27,. but preferably is slightly inclined to such position (seeFig. 1), so as to bite into the rind as it reaches the knives Thefriction of bevel 109 against the caster wheel causes rotation thereofin the direction shown by the arrows. Final setting of the knives incorrect position is determined by the operator, by trial methods, in thecase of each type or size of article being trimmed.

An important feature of the machine is the movement of the knives intocontact with the work after the turntable has been brought to a stop,for it has been found that if the work is indexed into waiting knives,erratic cuts occur. .As the knives contact the work, the rind isreceived at the intersection of their cutting edges and is sheared atits base. The upper and outermost knife 91 contacts the work 27 with itsslant face and rotates it by frictional engagement, so that the cuttingof the rind procoeds around the circumference of the wheel. Indexing ofthe work proceeds at a fixed rate and is so timed that the time betweensuccessive phases, that is, the interval when the pawl is returning, issufficient to permit at least one rotation of wheel 23 by the trimmingknives.

The knives of the trimming unit 32, for trimming the bottom rind, areshown in Fig. 4. The knives, indicated at 91" and 92' are identical withknives 91 and 92, respectively, but are arranged in an opposite sense,which may be described as mirror image of the arrangement of knives 91and 92. Since the slant of these lower knives is such that they tend tolift the wheel being trimmed, a hold-down device is necessary at thetrimming unit 32; This is provided in a roller 118, journaled on the endof an arm 119, carried on a bolt 121 threaded in the fixed central shaftof the turntable, the arm being fixed in position by a set screw 122, sothat roller 118 is incontact with the upper face of a wheel 27 at apoint between the center of the wheel and the trimming point when it isindexed at the station adjacent knives 91', 92'. As the action of thetrimming knives at the unit 31 tends to hold the work down upon itssupport, no hold-down device is required at that point.

The machine having been set in motion, all that is required of theoperator is to place the untrimmed articles over the pins 24 during theperiod of their travel from the ejecting mechanism to the first trimmer.In the particular arrangement shown, the articles first meet thetrimmers which trim the rind alongthe top edge of the article. As themachine comes to a stop in the position shown in Fig. 1, the twotrimming mechanisms are moved inwardly, simultaneously, into trimmingposition by the action of the valve mechanism 89. The knives being inmotion, the articles turn about their holding pins until the rinds areremoved, the dwell afforded by the turntable indeXing mechanism being ofsufficient duration to completely trim one side of the article at eachof the trimming stations. The trimmed article is now brought to theejecting station where it is stripped from the pin 24 and delivered tothe chute.

Should the machine be employed for trimming asingle rind only, one ofthe trimming units would be idled and the other trimming unit would beangularly adjusted to the location of the rind.

It will be seen that there has thus been provided a trimming cutterwhich is rapid and completely automatic in its operation, and in whichthe trimming operation is performed with requisite neatness andprecision by virtue of the circular knives. The turning of the work bythe knives ensures proper and accurate coordination and makes possiblean apparatus which is simple in structure. Furthermore, the generalarrangement of the knife units renders the cutter highly flexible and,therefore, adapted to a wide range of uses.

While a certain preferred embodiment has been shown and described, theinvention is not limited thereby since changes in the size, shape andarrangement, for instance, of the various parts may be made withoutdeparting from the spirit or scope of the appended claims.

What is claimed is:

1. In a machine for trimming a rotating work piece, a housing, a pair ofperipheral overlapping circular knives journaled in said housing, andmounting means for said housing comprising a first upright, a blockslidable and adjustably mounted on said first upright, a supportslidably mounted in said block in a direction transverse to said firstupright, a second upright carried by said support, a shaft connected tosaid housing and journaled in said second upright, means to adjust thetilt of said housing with respect to said Work piece and an armprojecting from said shaft and adapted to twist said shaft with respectto said second upright, whereby said knives are positioned against saidwork piece for the trimming operation and withdrawn from the work piecewhen the trimming operation is complete.

2. Ina trimming machine adaptedto trim curved work pieces, a housing, apair of peripherally overlapping circular knives adapted for rotation inopposite directions journaled in said housing, means to rotate saidhousing toward and away from said work piece, at least one of saidknives provided with a means for rotating said work piece during thetrimming operation and at least one of said knives having a cavity intowhich part of the work piece projects during the trimming operation.

3. In a trimming machine adapted to trim rind from two edges of a castorwheel simultaneously, two sets of peripherally overlapping circularknives, a housing for each set of knives in which said knives arejournaled for rotation, means to rotate said housing to bring each setof knives against a castor wheel before the trimming operation and toremove each set of knives from the castor wheel at the conclusion of thetrimming operation simultaneously, at least one knife in each set with acavity into which partof the castor wheel projects during the trimmingoperation, whereby each set of knives closely fits the contour of saidcastor wheel during the trimming operation.

4. In a machine for trimming a rotating Work piece, a housing, cuttingmeans journaled in said housing, and mounting means for said housingcomprising a first upright, a block slidably and adjustably mounted onsaid first upright, a support slidably mounted in said block in adirection transverse to said first upright, a second upright carried bysaid support, a shaft connected to said housing and journaled in saidsecond upright, means to adjust the tilt of said housing with respect tosaid work piece and means connected to said shaft to move said cuttingmeans to said work piece for the trimming operation and from said worpiece when the trimming operation is complete.

5. In a machine for trimming a rotating work piece, a housing, a pair ofperipheral overlapping circular knives journaled in said housing, andmounting means for said housing comprising a first upright, a blockslidably and adjustably mounted on said first upright, a supportslidably mounted in said block in a direction transverse to said firstupright, a second upright being hollow and having an aperture in thewall thereof carried by said support, a shaft connected to said housingand journaled in said second upright, means to adjust the tilt of saidhousing with respect to said work piece and means connected to saidshaft through said aperture to twist said shaft and move said knives tosaid work piece for the trimming operation and from said work piece whenthe trimming operation is complete.

6. In a machine for trimming a rotating work piece, a housing, cuttingmeans journaled in said housing, and mounting means for said housingcomprising a first upright, a block slidably and adjustably mounted onsaid first upright, a support slidably mounted in said block in adirection transverse to said first upright, a second upright beinghollow and having an aperture in the wall thereof carried by saidsupport, a shaft connected to said housing and journaled in said secondupright, means to adjust the tilt of said housing with respect to saidwork piece and an opening in said second upright, an arm attached tosaid shaft and projecting through said opening, and means attached tosaid arm to reciprocate the projecting end thereof, whereby to tilt saidhousing with respect to said work piece, for the trimming operation,means connected to said shaft through said aperture to twist said shaftand move said knives to said work piece for the trimming operation andfrom said work piece when the trimming operation is complete.

7. In a cutting device adapted to trim curved work pieces comprising afirst disc-shaped knife having a planar face on one side thereof and abeveled face on the other side thereof merging with said planar face toform a circular edge; a second disc-shaped knife having an annularplanar face on one side thereof framing a central dishlike cavity and abeveled face on the other side of said second knife merging with saidannular planar face to form a circular edge, the planar face of thefirst knife abutting and overlapping in the radial direction the annularface of the second knife.

8. In a cutting device adapted to trim curved work pieces comprising afirst disc-shaped knife having a planar face on one side thereof and abeveled face on the other side thereof merging with said planar face toform a circular edge; a second disc-shaped knife of greater thicknesshaving an annular planar face on one side thereof framing a centraldish-like cavity and a beveled face on the other side of said secondknife merging with said annular planar face to form a circular edge, theplanar face of the first knife abutting and overlapping in the radialdirection the annular face of the second knife.

9. In a cutting device adapted to trim curved work pieces comprising afirst disc-shaped knife having a planar face on one side thereof and abeveled. face on the other side thereof merging with said planar face toform a circular edge; a second disc-shaped knife having an annularplanar face on one side thereof framing a central dishlike cavity and abeveled face on the other side of said second knife merging with saidannular planar face to form a circular edge, the planar face of thefirst knife abutting and overlapping in the radial direction the annulatface of the second' knife andmeans to. drive each said knives inopposite directions.

10. In a pair of knives adapted to trim curved work pieces comprising afirst: disc-shaped knife havinga planar face on one side thereof and a;beveled face on the other side thereof merging with said planar face toform a circular edge; a second disc-shaped knife-having an annularplanar face on one side thereof framing a central dishlike cavity and abeveled face on the other side of said second knife merging with saidannular pli'mar face to form a second edge, the planarface' of, thefirst knife abutting and overl'appingin the radial direction the annularface of the second knife at least /1 of an inch.

References Cited in the filev of this patent UNITED STATES PATENTS

